1. Field of the Invention
The invention relates to a brake booster for a motor vehicle brake system of the brake-by-wire type, which can be activated both by means of a brake pedal and as a function of a driver's request, as well as independently of the driver's wish by means of an electronic control unit, wherein the coupling of the brake pedal, or of a force transmitting part which is permanently connected to the brake pedal, to an input member of the brake booster is embodied in such a way that the brake pedal or the force transmitting part which is permanently connected to the brake pedal can carry out a limited relative movement with respect to the input member, which ensures, in particular in the brake-by-wire operating mode, a decoupling of the force transmitting connection between the brake pedal or the force transmitting part which is permanently connected to the brake pedal.
2. Description of the Related Art
A brake booster is known from European patent EP 0 417 945 B1. A piston rod which forms the input member of the previously known brake booster has a longitudinal opening which holds a bolt which is permanently connected to a brake pedal. The longitudinal opening permits a limited relative movement of the input member with respect to the bolt or the brake pedal with the result that when the brake booster is used in a case of drive slip control or when the brake booster is actuated independently of the driver's wish, the input member moves in the direction of activation while the brake pedal remains stationary. The large amount of friction which occurs between the input member and the bolt causes a large amount of wear of said parts, causes them to corrode and generates noise which is felt to be unpleasant and disruptive by the driver of the vehicle.